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pH-Induced dissociation of bovine casein micelles. I. Analysis of liberated caseins

Published online by Cambridge University Press:  01 June 2009

Douglas G. Dalgleish  and
Andrew J. R. Law
Douglas G. Dalgleish
Affiliation:
Hannah Research Institute, Ayr KA6 5HL, UK
Andrew J. R. Law
Affiliation:
Hannah Research Institute, Ayr KA6 5HL, UK
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Summary

The dissociation of caseins of different types from casein micelles in milk, acidified to different pH values in the range 4·9–6·7, and at temperatures of 4, 20 and 30 °C, has been studied. In contrast to a number of previous findings, it was shown that caseins of all types were dissociated from the micelles, although in all cases β-casein was in highest concentration. The amounts and proportions of all of the caseins were found to be pH- and temperature-dependent, especially the former. Studies of the proportions of the different caseins liberated suggested that, at a defined temperature, the proportions of κ;- and αs2-caseins were independent of pH, while the proportions of β- and αsl-caseins were variable, changes in one being compensated by changes in the other. The manner in which the proportions of the αsl-casein and β-caseins changes with pH was found to be temperature-dependent.

Type
Original articles
Information
Journal of Dairy Research , Volume 55 , Issue 4 , November 1988 , pp. 529 - 538
Copyright
Copyright © Proprietors of Journal of Dairy Research 1988

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References

REFERENCES

Banks, J. M., Stewart, G., Mum, D. D. & West, I. G. 1987 Increasing the yield of Cheddar cheese by the acidification of milk containing heat-denatured whey protein. Milchwissenschaft 42 212–215Google Scholar
Chaplin, L. C. 1984 Studies on micellar calcium phosphate: composition and apparent solubility product in milk over a wide pH range. Journal of Dairy Research 51 251–257Google Scholar
Davies, D. T. & Law, A. J. R. 1983 Variation in the protein composition of bovine casein micelles and serum casein in relation to micellar size and milk temperature. Journal of Dairy Research 50 67–75Google Scholar
Davies, D. T. & Law, A. J. R. 1987 Quantitative fractionation of casein mixtures by fast protein liquid chromatography. Journal of Dairy Research 54 369–376Google Scholar
Gordon, W. G. & Groves, M. L. 1975 Primary sequence of beta, gamma, and minor caseins. Journal of Dairy Science 58 574–582Google Scholar
Holt, C. 1982 Inorganic constituents of milk. III. The colloidal calcium phosphate of cow's milk. Journal of Dairy Research 49 29–38CrossRefGoogle ScholarPubMed
Holt, C., Davies, D. T. & Law, A. J. R. 1986 Effects of colloidal calcium phosphate content and free calcium ion concentration in the milk serum on the dissociation of bovine casein micelles. Journal of Dairy Research 53 557–572CrossRefGoogle Scholar
McGann, T. C. A. & Pyne, G. T. 1960 The colloidal phosphate of milk. III. Nature of its association with casein. Journal of Dairy Research 27 403–417Google Scholar
Pyne, G. T. & McGann, T. C. A. 1960 The colloidal phosphate of milk. II. Influence of citrate. Journal of Dairy Research 27 9–17CrossRefGoogle Scholar
Reimerdes, E. H. & Klostermeyer, H. 1976 [Temperature-dependent changes in milk and milk products. 1. Changes in the ratio of micelle protein to serum protein during refrigeration of milk.] Kieler Milchwirtschaftliche Forschungsberichte 28 17–25Google Scholar
Roefs, S. P. F. M., Walstra, P., Dalgleish, D. G. & Horne, D. S. 1985 Preliminary note on the change in casein micelles caused by acidification. Netherlands Milk and Dairy Journal 39 119–122Google Scholar
Rose, D. 1968 Relation between micellar and serum casein in bovine milk. Journal of Dairy Science 51 1897–1902CrossRefGoogle Scholar
Schmidt, D. G. 1982 Association of caseins and casein micelle structure. In Developments in Dairy Chemistry- 1 Proteins pp. 61–86 (Ed. Fox, P. F.) London: Applied Science PublishersGoogle Scholar
Schmidt, D. G. & Poll, J. K. 1986 Electrokinetic measurements on untreated and heated casein micelle systems. Netherlands Mille and Dairy Journal 40 269–280Google Scholar
Snoeren, T. H. M., Klok, H. J., Van Hooydonk, A. C. M. & Damman, A. J. 1984 The voluminosity of casein micelles. Milchwissenschaft 39 461–463Google Scholar
Swaisoood, H. E. 1982 Chemistry of milk protein. In Developments in Dairy Chemistry-1. Proteins pp. 1–59 (Ed. Fox, P. F.) London: Applied Science PublishersGoogle Scholar
Tanford, C. 1980 The Hydrophobic Effect. Formation of Micelles and Biological Membranes 2nd ednNew York: John WileyGoogle Scholar
Tarodo De La Fuente, B. & Alais, C. 1975 Solvation of casein in bovine milk. Journal of Dairy Science 58 293–300CrossRefGoogle Scholar
Trop, M. & Kushelevsky, A. 1985 The reaction of glucono delta lactone with proteins. Journal of Dairy Science 68 2534–2535Google Scholar
Van Hooydonk, A. C. M., Haoedoorn, H. G. & Boerrioter, I. J. 1986 pH-induced physico-chemical changes of casein micelles in milk and their effect on renneting. 1. Effect of acidification on physico-chemical properties. Netherlands Milk and Dairy Journal 40 281–296Google Scholar